Feeding mechanism for sewing machines



Oct. l, 1929. F. M. CARD FEEDING MECHANISM FOR SEWING MACHINES FiledAug. l, 1928 2 Sheets-Sheet Frederic Oct. l, 1929. F. M. CARD 1,729,994

FEEDING MECHANISM FOR SEWING MACHINES Filed Aug. 1, 1928 2 Sheets-Sheet2 gn/manto@ Frederic Jil-67W 1,44 liv Patented Oct. l, 1929 PATENTOFFICE FREDERIC IVI. CARD, OF BRIDGEPORT, CONNECTICUT, ASSIGNOR TO THESINGER MANU- FACTURING COMPANY, OF ELIZABETH,

JERSEY NEW JERSEY, A CORPORATION 0F NEW FEEDING MECHANISM FOR SEWINGMACHINES Application filed August 1,

This invention relates to improvements in feeding mechanisms for sewingmachines and has for its object to provide means for more etlicientlyadvancing the work past the stitchtorming mechanism of sewing machinesof more particularly the work-supporting post and cylinder work-armtypes.

In sewing machines of the vertical worksupporting post type it has beena common practice to employ a four-motion feeding mechanism in which thefeed-dog has a decidedly elliptical path of movement, rendering itdil'licult to prevent a back-drag upon the work during the returnmovement of the feed-dog.

In the present improvement, the feed-dog is maintained substantiallyparallel to the plane of the work throughout its complete feedingmovement, instead of being tilted at constantly varying angles as in theelliptical movement type of feed-dogs. Vhile prior feeding mechanismshave heretofore been devised to obtain a rectangular path of movementfor the feed-dogs, such mechae nisms are unadapted for embodiment in theconstricted space available in post machines or are not designed to meetpresent high speed requirements.

In a preferred embodiment of this invention, a work-supporting post typeof sewing machine is provided with a feeding mechanism in which thefeed-dog is supported by a carrier of which one end is pivotallyconnected to the upper arm of a rocking feed-lever, disposed lengthwiseof the post and having for its primary function to impart work-advancingand return movements to the feed-dog. This lever is fulcrumedintermediate its ends upon aslidc-block vertically reeijnocatt-d inguideways within the work-supportinf post. whereby said lever has for anadditional function the raising and lowering of one end of the feed-dog.The other end of the feed-dog carrier is slidingly supported upon theupper end of a feed-lift bar vertically reciproeated in bearingsprovided within the work-supporting post. By properly timing the risingand falling movements of the feed-lift bar and the feed-lever supportingslide-block with 1928. Serial No. 296,678.

respect to the rocking movements of said feed-lever, substantiallyrectangular movements may be imparted to the feed-dog.

The forked lower end of the feed-lever is engaged by a crank on theforward end of a rock-shaft journaled beneath the bed-plate of themachine and having the usual pitman connections with an adjustableeccentric upon the main-shaft journaled in the bracketarm of themachine. The slide-block is provided with a depending arm havinglinkconnections with a crank-arm upon a rockshaft actuated by pitman andeccentric connections with a loop-taker actuating shaft journaledbeneath the cloth-plate. The feedlift bar is secured for verticaladjustment upon a fork engaged by another eccentric upon said loop-takeractuating shaft, which shaft is driven in one-to-one relation withrespect to the rotations of the main-shaft by suitable belt-connectionstherewith.

In the accompanying drawings, Fig. l is a longitudinal section of asewing machine in which the present improved feeding meehanism has beenembodied. Fig. 2 is a bottom plan view of the sewing machine. Fig. 3 isa vertical section of the work-supporting post, omitting the loop-taker.Fig. 4. is a perspective view of the feeding mechanism. Fig. 5 is adetail view in elevation of the adjustable connection between thefeedlift bar and the fork at its lower end.

Referring to the drawings, the feeding mechanism is illustrated asembodied in a sewing machine having a bed-plate 1 from one end of whichrises a hollow post 2 upon which is secured the usual standard 3 of anoverhanging bracket-arm 4 terminating in a head 5. The mechanismcontained within the bracket-arm is that of a well known type of zigzagstitch sewing machine illustrated, for instance, in the U. S. patent toC. F. Gray, No. 933,032, August 3l, 1909. In general, this mechanismcomprises a rotary main or actuating shaft 6 carrying at one end adriving pulley 7 and at its opposite end a crank-plate 8 provided with acrankpin 9 connected by means of a link l() with a needle-bar 1lcarrying at its lower end a needle 12.

The needle-bar 11 is journaled for endwise reciprocation in suitablebearings provided in a vibratory frame 13 pivoted at its upper endwithin the head 5 upon a fulcrum-stud 14. Suitably connected with theframe 13 is one end of a link-bar 15 of which the opposite end is formedas a forli` 16 between the spaced member of which is disposed atriangular cam 17 carried by a transverse camshaft 18. Fixed upon thecam-shaft 18 is a gear-wl'recl 19 driven by a smaller gear 20 upon themain-shaft 6 at one-half the speed of rotation of the main-shaft. Thelink-bar 15 receives vibratory movements upon its pivotal connectionwith the frame 13 from the actuating cam 17, but is free to move endwisein relation to said cam. In order that the sidewise actuation impartedto the linlfbar by the cam 17 may be partially converted into endwisemovement to thereby vil ate the needle laterally, said link-bar isconnected by means of the link 2l with an adjustable fulcrum-stud 22, asmore fully described in said prior Patent No. 933,032.

Rising from the bed-plate 1 at the forward end thereof is awork-supporting post 23, which is substantially rectangular intransverse section and supports av throat-plate 24 upon its upper end.Housed within said post 23 directly below the throat-plate 24 is aloop-taker 25 of the rotary-hook type, carrying a mass of under threadaround which the needle-thread loops are cast in the formation oflock-stitches. The axis of rotation of the loop-taker is horizontal andtransverse to the plane of lateral vibration of the nee` dle. Theloop-taker 25 is carried by a short shaft 26 ournaled in thebearing-bushing 27 located in a suitable aperture provided in the post23,` said shaft 26 carrying a bevel-gear 28 in mesh with a similar gear29 upon the upper end of a vertically disposed, intermediate shaft 30.rlhe vertical shaft 30 is journaled in bearing-lnishings 31 and 32 livedin apertured lugs 33 and 34 disposed within the post 23. At its lowerend, the shaft 30 carries a bevel-gear 35 driven by a gear 36 fixed uponthe forward end of a loop-taker actuating shaft 37 journaled in suitablebearings provided at the under side of the bed-plate 1. The ratio ofgears 35 and 36 is such that the vertical shaft 30 rotates twice foreach rotation of the shaft 37. Sccured upon the shaft 37 is a pulley 38engaged by a belt 39 passing over a pulley 40 upon the main-shaft 6, theshaft 37 rotatingl once for cach rotation of the main-shaft 6.

Opposed to the usual presser-foot 41, in advancing the work past thestich-forming` mechanism, is a feed-dog 42 operatingr through slots as43 provided in the throat` plate 24. The feed-dog 42 has a laterallyextending shank 44 secured by screws 45 upon a vertically disposed plateor feed-dog carrier 46 free to swing upon a pivot-bolt 47 in the upperend of a feed-lever 48. The feed-lever 48 is provided with a verticallydisposed guide-slot 49 receiving the carrierplate 46 and serving tobrace the latter, said feed-lever being not only actuated to impartwork-advancing -and return movements to the feed-dog, but also to raiseand lower one end of said feed-dog. Accoroingly the feedlcver 48 isformed intermediate its ends with an apertured boss 50, in which issecured a fulcruin-pin 51 journaled in alined apertures in spaced lugsas 52, projecting from one side of a slide-block 53. The slide-bloeit 53is confined to vertical reciprocation in an undercut guideway 54provided within the post 23, in one of the walls thereof. Dcpendingi'rom said slide-block is an arm 55, connected by means of a link 56with a cranl-iarm 57 having a split hub clamped by means of a screw 58upon one end of a short feedlift rock-shaft 59. rlhc rock-shaft 59 isourualed in apertured bearing lugs, as 60, at the under de of thebed-plate 1 and has another ritt-aria 61 suitably connected to one end apitnian 62 ot' which the opposite end is 'forzpei'l as a strap 63embracing an eccentric tupon the actuating shaft 37.

'ihc feed-lever 48 is forked at its lower end to slidingly receive apivot-block 65 upon a crai'il-piu 66 of an arm 67 extending laterallyfrom a feed-shaft 68. T he feed-shaft 68 is journaled in apcrturedbearing lugs, as 69, at tlie under side of the bed-plate 1 and carries acrank-arm 70 suitably connected to a vertically directed pitman 71having at its upper end a split sig-ap 72 embracing an adjustableeccentric 73 upon the main-shaft 6. The adjustable eccentric 73 isconstructed substantially in accordance with the disclosure in the U. S.patent to Dial et al., No. 718,988, January 27, 1903, and it istherefore deemed unneccesary to herein describe the saine in detail.

The feed-dog carrier 46 is forked to provide a slot 74 at its endopposite to the pivot-bolt 47, said slot 74 slidingly receiving aguideblock 75 pivotally supported between the spaced members of a fork76 at the upper end of a feed-lift bar 77. rllhis bar 77 is journaledfor vertical reciprocation in a bearinglug 78 within the post 23 and inan aperture in the lug 34, the flattened lower portion 79 oi' said barbeing slidingly fitted to a grooved guideway 8() formed in the rear faceof a fork 81 stradding an eccentric 82 upon the actuating shaft Theflattened portion 79 0l of the feed-lift bar is provided with avertically elongated slot 83 through which passes a securing screw 84threaded into the fork 81.. whereby the bar 77 may be verticallyadjusted with respect to said fork. In order to more accurately efectthis adjustment, an adjusting screw 85 is threaded into the lower end ofthe bar 77, said screw 85 having a grooved head 86 engaged by spacedprojections on a meager i detaining-plate 87 secured upon the under sideof the fork 8l, whereby the plate 87 holds the screw 85 against endwisemovement to effect vertical adjustment of the bar 77 upon manipulationof the screw.

It will be understood that by vertically ad justing the bar 77, one endof the feed-dog 42 may be projected the desired distance above thethroat-plate in accordance with the character of the work to bestitched. The other end of the feed-dog may likewise be adjustablyraised or lowered by loosening the clamp-screw 58 of the crank-arm 57,this adjustment being permitted by reason of the forked lower end of thefeed-lever 48.

The operation of the present improved feeding mechanism will be readilyapparent from the foregoing description. The rocking feed-lever 48imparts Work-advancing and return movements to the feed-dog of an extentwhich may be predetermined by adj ustment of the feed-eccentric upon themainshaft 6. The feed-dog may be maintained horizontal throughout itsentire movement by simultaneously raising and lowering opposite endsthereof as described, consequently obviatingr all back-drag upon thework by the feed-dog during its return movements, regardless of thestitch-length selected.

Having thus set forth the nature of the invention, what I claim hereinis:

1. Feeding mechanism for sewing machines, comprising a feed-dog carrier,a feedlever, a pivotal connection between said carrier and thefeed-lever, a feed-lift bar, an operative connection between saidfeed-lift bar and the carrier spaced in the direction of feed from thepivotal connection of the feedlever therewith, means for verticallyreciprocating the feed-lift bar, means for vertically reciprocating thefeed-lever, and means for rocking said feed-lever to impartwork-advancing and return movements to the feeddog carrier.

2. Feeding mechanism for sewing machines, comprising a feed-dog carrier,a feedlever, a pivotal connection between said carrier and thefeed-lever, a vertically reciprocatory slide, a pivotal support for thefeedlever upon said slide, a feed-lift bar, an operative connectionbetween said feed-lift bar and the carrier spaced in the direction offeed from the pivotal connection of the feedlever therewith, means forvertically reciprocating the feed-lift bar, means for verticallyreciprocating said slide, and means for rocking said feed-lever uponsaid slide to impart work-advancing and return movements to the feed-dogcarrier.

3. Feeding mechanism for sewing machine-s, comprising a feed-dogcarrier, a feedleve-r., a pivotal connection between said carrier andthe feed-lever, a feed-lift bar, an operative connection between saidfeed-lift bar and the carrier spaced in the direction of feed 'from thepivotal connection of the feedlever therewith, means for verticallyreciprocating the feed-lift bar including an adj ustable connection fordetermining the extent of rising movement of said feed-lift bar, meansfor verticallyI reciprocatingl the feed-lever, and means for rockingsaid feed-lever to im.- part work-advancing and return movements to thefeed-dog carrier.

4. Feeding mechanism for sewing ma.- chines, comprising afeed-dogcarrier, a feedlever, a pivotal connection between said carrier and thefeed-lever, a vertically reciprocatory slide, a pivotal support for thefeed-lever upon said slide, means for rocking said feedlever upon saidslide to impart work-advancing .and return movements to the feed-dogcarrier, means for vertically reciprocating said slide to impart risingand falling movements to one end of said carrier, and additionalfeed-lift means for imparting rising and falling movements to the otherend of said carrier.

5. Feeding mechanism for sewing machines, com p-rising a feed-dogcarrier, a feedlever, a pivotal connection between said carrier and thefeed-lever, a vertically reciprocatory slide, a pivotal support for thefeed-lever upon said slide, means for rocking said feedlever upon saidslide to impart work-advancing and ret-urn movements to the feed-dogcarrier, means for vertically reciprocating said slide to impart risingand falling movements to one end of said carrier, additional feed-liftmeans for imparting rising and falling movements to the other end ofsaid carrier, and means for adjustably determining the extent of risingmovement of one end of said carrier with respect to the rising movementof the other end thereof.

6. In a sewing machine, the combination with stitch-forming mechanismcomprising a reciprocatory needle, a loop-taker complemental to saidneedle in the formation of lock-stitches, an actuating shaft andconnections therewith for reciprocating said needle, and a loop-takeractuating shaft, of feeding mechanism including a feed-dog carrier, afeed-lever pivotally connected with said carrier, operative connectionsbetween said mainshaft and the feed-lever for rocking said lever toimpart work-advancing and return movements to the feed-dog carrier,operative connect-ions between said feed-lever and the looptakeractuating shaft for raising and lowering said feed-dog carrie-r, afeed-lift bar independent of said feed-lever, means for verticallyreciprocating said feed-lift bar from the loop-taker actuating shaft,and an operative connection between said feed-lift bar and the feed-dogcarrier.

7. In a sewing machine having a bed-plate, a vertically disposedwork-supporting post rising from said bed-plate, and an overhangingbracket-arm, a needle, a loop-taker housed within said post, andwork-feeding mechanism including a feed-dog carrier, a verticallyreciprocatory slide housed within said post, a feed-lever fulcrumed uponsaid slide, av guideway or said slide upon one of the walls of saidpost, a pivotal connection between said feed-lever and the feed-dogcarrier, a feed-lift bar housed Within said post, an operativeconnection between the feed-lift bar and the feed-dog carrier, means forVertically reciprocating said slide, means for vertically reciprocatingsaid feed-lift bar, and nli'ens for rocking the feed-lever upon said s 1e.

In testimony whereof, I have signed my name to this specification.

FREDERIC M. CARD.

